The present invention relates to an information processing apparatus and method and a program. More particularly, the present invention relates to an information processing apparatus and method and a program that are capable of searching each of a plurality, if any, of sets subject to search for desired elements at high speeds.
Many high-seed search methods have been proposed to solve the so-called nearest neighbor search problem in which, given an n-dimensional input vector, a nearest neighbor vector neighborhood for the input vector is obtained from a set of n-dimensional vector groups.
For example, a method was proposed in which, of N centroid vectors v(i), a predetermined centroid vector is set to remarkable vector v1 and, of distances between remarkable vector v1 and centroid vector v(i), a distance near remarkable vector v1 at N/k-th order is set to radius distance DR of the remarkable vector to compare distance D1 between input vector u and remarkable vector v1 and DR/2 that is ½ of radius distance DR, thereby determining a range of search for an optimum vector in accordance with a result of the comparison (refer to Japanese Patent No. 3273581 for example).
Also, such a search method is used to search for feature vectors in image recognition processing for example. A feature vector is obtained by combining feature parameters and vectorizing the combination. Comparison between the feature vector of an image subject to processing and the feature vector of a prepared model image may identify a relationship between the image subject to processing and the model image. The image recognition processing based on feature vectors allows the recognition that is hardly affected by viewpoint change or brightness change.